KAIST

< (From left) Professor Seungbum Hong, Ph.D candidate Seonghyun Kim, Dr. Youngwoo Choi, and Dr. Yoonhan Cho >

A crucial clue to simultaneously increasing electric vehicle (EV) driving range and battery lifespan has been discovered. A research team at our university has observed the exact moment of degradation in lithium metal batteries at the nanoscale (approximately 1/100,000th the thickness of a human hair) and identified the fundamental cause of performance decline. This is evaluated as a significant turning point in accelerating the commercialization of next-generation batteries.

KAIST announced on May 10th that a research team led by Professor Seungbum Hong from the Department of Materials Science and Engineering has identified the degradation mechanism of the lithium metal anode, a core component of next-generation batteries.

Lithium metal is dubbed a "dream battery material" due to its significantly higher energy density compared to conventional batteries. However, the rapid decline in performance after repeated charge and discharge cycles has been the biggest obstacle to commercialization. In particular, when lithium is deposited or stripped irregularly, it can form "dead lithium"—lithium that is electrically disconnected—which leads to performance degradation and poses safety risks.

The research team utilized in situ electrochemical atomic force microscopy (EC-AFM), which allows for real-time observation of the battery interior, to track the entire process of lithium deposition (plating) and removal (stripping). As a result, they confirmed that the lithium reaction does not occur uniformly across the entire surface but occurs selectively at specific locations.

<Overview of the EC-AFM Measurement Process>

Specifically, in porous regions with rough surfaces, voids were easily formed when lithium was stripped away, leading to the creation of "dead lithium" that becomes electrically isolated. This phenomenon acts as a direct cause of the sudden decline in battery performance.

The significance of this study lies in experimentally identifying where and how lithium metal batteries are damaged. Furthermore, it proved that the "initial morphology," where lithium is first formed, is a key variable that determines the long-term lifespan of the battery.

<Height Maps and Surface Slope Maps During the 1st–3rd Plating/Stripping Processes>

Accordingly, it is expected that if the surface where lithium forms is controlled uniformly and precisely in the future, battery life and stability can be dramatically improved. This suggests a design direction that can simultaneously achieve increased EV driving range and the development of long-life batteries.

Professor Seungbum Hong stated, "This research is highly significant as it directly confirmed the cause of battery performance degradation at the nanoscale. It will serve as an important foundation for developing safer and longer-lasting next-generation batteries."

Seonghyun Kim, a PhD student in the Department of Materials Science and Engineering, participated as the lead author. The study was published on February 24, 2026, in ACS Energy Letters, a prestigious international academic journal in the fields of materials science, chemistry, and chemical engineering, and was selected as a cover article.

※ Paper Title: Spatially Selective Lithium Plating and Stripping in Lithium Metal Anodes, DOI: https://doi.org/10.1021/acsenergylett.6c00122

< Photo of Selection as ACS Energy Letters Cover Paper >

Meanwhile, this research was conducted with support from LG Energy Solution and the Future Pioneering Convergence Science and Technology Development Program (RS-2023-00247245) of the National Research Foundation of Korea, funded by the Ministry of Science and ICT.